Lattice Filter Design Module
As integrated photonic designs become more complex, there is a need to move the design process to higher levels of abstraction to manage the complexity. The first step in this process was the development of process design kits (PDKs) that include standard photonic building blocks as well as enough information about the manufacturing process to enable designers to design their own specialized components. PDKs have advanced in this regard, with many foundries now supplying extensive information on their waveguide characteristics such as effective index, group index, dispersion and loss, and their dependence on waveguide width and bending radius. Additionally, PDK building blocks can have known or user-defined optical specifications; for example, a directional coupler with a given coupling ratio. This enables algorithms that use PDK information to synthesize a layout with a desired optical function.
The OptoDesigner Lattice Filter Design Module automatically synthesizes optical filters given a user-directed optical specification. The software uses optimization algorithms to calculate a set of coupling ratios and phase shifts for a technology-agnostic filter based on a concatenated Mach-Zehnder Interferometer architecture. Once generated, the software can then synthesize a technology specific instance of the filter using information from the targeted foundry PDK. The filter is generated using PDK-based photonic building blocks and waveguides tuned with correct group and optical lengths.